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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Compare water quality across 11 counties in Arizona
11 counties ranked by average water quality score
| Rank | County | Avg Score | Grade | Cities | Population | Score Range |
|---|---|---|---|---|---|---|
| 1 | Cochise County | 96 | A | 2 | 36,701 | 96 - 96 |
| 2 | Coconino County | 88 | B | 1 | 79,796 | 88 - 88 |
| 3 | Pinal County | 86 | B | 4 | 170,807 | 77 - 100 |
| 4 | Pima County | 86 | B | 3 | 766,246 | 73 - 98 |
| 5 | Navajo County | 82 | B | 1 | 17,139 | 82 - 82 |
| 6 | Maricopa County | 81 | B | 15 | 3,850,739 | 54 - 98 |
| 7 | Yavapai County | 78 | C | 3 | 110,288 | 51 - 95 |
| 8 | Mohave County | 77 | C | 3 | 135,940 | 44 - 95 |
| 9 | Gila County | 73 | C | 1 | 17,682 | 73 - 73 |
| 10 | Yuma County | 68 | D | 3 | 157,166 | 53 - 95 |
| 11 | Santa Cruz County | 67 | D | 1 | 22,000 | 67 - 67 |
Our county-level water quality analysis aggregates data from municipal water systems across Arizona. Each county's score represents the average water quality across all analyzed cities within that county, weighted by population served.
With 11 counties and 37 cities analyzed, this data helps residents understand regional water quality patterns in Arizona. County scores range from 44/100 to 100/100, reflecting the diversity of water sources and treatment infrastructure across the state.
Currently, 2 counties in Arizona have average scores below 70, indicating potential water quality concerns. Residents in these areas should review their city's specific report and consider water filtration options.